COLIBRE模拟中z≳10的JWST星系的前身
The progenitors of $z\gtrsim10$ JWST galaxies in the COLIBRE simulations
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中文总结 AI 辅助
本研究通过COLIBRE模拟发现，标准星系形成物理与ΛCDM宇宙学可解释z≳10处JWST发现的极端星系，仅紫外光度和尘埃质量的差异或源于高红移 grain 生长速率与恒星初始质量函数的不确定性。
中文摘要 AI 辅助
詹姆斯·韦布空间望远镜（JWST）已在红移z≳10处发现了大量发光星系（M_UV≲-20），这一发现被广泛认为对ΛCDM宇宙学框架内的星系形成模型构成了挑战。本研究在COLIBRE星系形成模拟中搜寻这些JWST星系的对应天体。尽管这些模拟未经过任何z>0观测的调谐，我们仍发现了一群COLIBRE星系，其性质与JWST星系相似，并将其追溯至最早的演化阶段（z≃25），以探究星系形成的开端。我们研究了星系恒星质量、大小、恒星形成率、紫外（UV）光度、金属丰度、中心黑洞质量以及分子气体和尘埃含量的演化，发现其与z>10处观测推断的性质吻合良好，仅紫外光度和尘埃质量存在差异——COLIBRE对紫外光度的预测偏低，对尘埃质量的预测偏高。我们的结果表明，COLIBRE采用的标准星系形成物理和ΛCDM宇宙学足以重现最极端的z>10 JWST星系的广泛性质，包括其致密大小、恒星质量、气体含量和金属丰度。我们还指出，紫外光度和尘埃质量的差异可归因于高红移处 grain 生长速率的不确定性，可能还与顶部重的恒星初始质量函数有关。这些发现为标准宇宙学模型能够自然解释早期宇宙中最极端星系的形成提供了有力证据。
英文摘要
JWST has revealed a large population of luminous galaxies ($M_{\rm UV}\lesssim -20$) at redshifts $z \gtrsim 10$, widely interpreted as posing a challenge to models of galaxy formation within the $Λ$CDM cosmology. Here, we search for counterparts of the JWST galaxies in the COLIBRE simulations of galaxy formation. Although these simulations have not been tuned to reproduce any $z > 0$ observations, we find a population of COLIBRE galaxies with properties similar to those of the JWST galaxies, and trace them to their earliest evolutionary phases, $z\simeq25$, to investigate the onset of galaxy formation. We study the evolution of galaxy stellar masses, sizes, star formation rates, UV magnitudes, metallicities, central black hole masses, and molecular gas and dust content, finding good agreement with observationally inferred properties at $z > 10$, except for UV magnitudes and dust masses, which COLIBRE underpredicts and overpredicts, respectively. Our results indicate that the standard galaxy formation physics and $Λ$CDM cosmology adopted in COLIBRE are sufficient to reproduce a broad range of properties of the most extreme $z > 10$ JWST galaxies - including their compact sizes, stellar masses, gas content, and metallicities. We show that the discrepancies with the UV magnitudes and dust masses can both be attributed to the uncertain rate of grain growth at high redshift, possibly alongside a top-heavy stellar initial mass function. These findings provide strong evidence that the standard cosmological model can naturally explain even the most extreme galaxies in the early Universe.
